The present invention relates generally to machine tools and more particularly to a device for enabling fine adjustment of the tool seat of a machine tool. The device of the present invention is of the type comprising a pneumatic-hydraulic pressure transmitter connected with a pressure transducer which operates as a positioning member to enable adjustment of a tool seat in response to pressure applied thereto. In devices of this type, the pressure transmitter includes a hydraulic cylinder having a hydraulic piston in sealed sliding engagement therein operating in fixed engagement with a pneumatic piston sealed by means of a flexible diaphragm which is clamped between the pneumatic piston and the housing of the pressure transmitter. Pressure applied to the pressure transducer operates by means of a spring force to adjustably position a tool seat which may be mounted upon the pressure transducer for movement parallel to itself by means of at least one expansion box arranged within the pressure transducer.
In a known device of this type, the pressure transducer or positioning member may consist of two flange-like parts interconnected by a pair of leaf springs having a pair of extensions which are in opposed relationship facing each other. Two adjacent expansion boxes are disposed therebetween and the pressure transmitter is accommodated in a shank having a face upon which the positioning member is flanged.
Designs of this type have been found costly. Their various components are difficult to produce and manufacture because they involve complicated shapes. Furthermore, assembly of such devices requires much time. The pairs of expansion boxes must each have identical positioning properties. Also, the field of application of this type of device is limited because of the necessity for maintaining a fixed configuration of the pressure transducer and positioning member. Due to the fact that the pressure transmitter and the positioning member are directly interconnected, and therefore form a relatively large mass, the mass forces of the machine tool components supporting the device cause error in the positioning signal and, as a result, error in the associated movements. Although balancing weights may provide a remedy of sorts, they cause the production problems to become even more difficult. In this connection it should be recognized that the interference factors of fine adjustment devices of this type are inherently of a magnitude in the order of their travel distances.
Accordingly, the present invention is aimed toward provision of a device enabling fine adjustments of tool seats which is arranged in a manner permitting the components thereof to be formed as separate modules which may be operatively combined in a variety of desired modes. The invention is intended to enable the components to be structured in a simpler configuration and one which is easier to assemble and manufacture. By utilization of the present invention the components thereof may be combined in such a manner that when they are applied in connection with the moving parts of a machine tool, reactions due to the resultant mass forces upon the positioning signal are greatly reduced as a result of advantages flowing from the particular design and arrangement of the pressure transmitter and positioning member. Furthermore, the invention permits avoidance of error in the positioning signal which may be caused by leakage losses in the pressure transducer.